Residential range rated 15kw

Ravenvalor

Ravenvalor

Senior Member
Location
Piedmont region of NC
Greetings and thank you for assistance in helping me understand this code question.

I have to pull a new residential range circuit. The new range installation manual requires a standard 14-50 receptacle and power cord. However the range nameplate rating is 15kw at 240volt. 15000 / 240 =62.5 * 1.25 = 78amps which bumps up to an 80amp circuit. Should I pull an 80 amp circuit or a 50 amp circuit?

Thank you for the great advice.
I really appreciate it.
 
You're calculation is incorrect. First you do not add 25% to the load as a range is not a continuous load by definition. Also for a single range you can use the demand factor in T220.55. Without doing the calculation the 50 amp circuit is likely correct.
 
infinity said:
You're calculation is incorrect. First you do not add 25% to the load as a range is not a continuous load by definition. Also for a single range you can use the demand factor in T220.55. Without doing the calculation the 50 amp circuit is likely correct.
Click to expand...
Thank you for the invaluable help. That’s what I get for not understanding the code.
Have a great day.
 
infinity said:
You're calculation is incorrect. First you do not add 25% to the load as a range is not a continuous load by definition. Also for a single range you can use the demand factor in T220.55. Without doing the calculation the 50 amp circuit is likely correct.
Click to expand...
Just to follow up.
I called a local electrical inspector and he agreed with you that it should be on a 50-amp breaker per the NEC. However he did not feel comfortable recommending it until I first called the manufacturer. So I called them and the person I spoke with said maximum allowable breaker size is 40-amps. They want 40- in order to protect the range.
Electrofelon may be correct they have integrated in the range some sort of load management software.
Thanks for the great advice.
 
Ravenvalor said:
So I called them and the person I spoke with said maximum allowable breaker size is 40-amps. They want 40- in order to protect the range.
Click to expand...
Does it say in the installation instructions that a 40 amp is the maximum size circuit permitted?
 
Ravenvalor said:
Greetings and thank you for assistance in helping me understand this code question.

I have to pull a new residential range circuit. The new range installation manual requires a standard 14-50 receptacle and power cord. However the range nameplate rating is 15kw at 240volt. 15000 / 240 =62.5 * 1.25 = 78amps which bumps up to an 80amp circuit. Should I pull an 80 amp circuit or a 50 amp circuit?

Thank you for the great advice.
I really appreciate it.
Click to expand...

A range is a non continuous load, and using 220.55 to size the branch circuit for a range with a 15kw nameplate ratng , after the 220.55 demand is applied it only needs a 40 amp circuit (9.2kw) . If you use 220.55 a 40 amp circuit is good for up to a 16.5kw range


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infinity said:
Does it say in the installation instructions that a 40 amp is the maximum size circuit permitted?
Click to expand...

Using 220.55 to size a 15kw range after applying the demands it comes out to 9.2kw so a 40 amp circuit is all you need if sized by using 220.55


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infinity said:
That is the minimum size permitted but can you use a 50 amp circuit?
Click to expand...

Unless the manufacturer requires a 40 amp circuit, but you are not restricted to using 220.55 we have the availability to size the circuit to the kw on the nameplate if we choose to I’ve never seen a cut sheet restricts above the min allowed


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Jaybone812 said:
Unless the manufacturer requires a 40 amp circuit, but you are not restricted to using 220.55 we have the availability to size the circuit to the kw on the nameplate if we choose to I’ve never seen a cut sheet restricts above the min allowed
Click to expand...
That's why I asked the question in post #6 regarding the instructions. I would be surprised if a 15 kw range was limited to a 40 amp branch circuit.
 
Ravenvalor said:
Greetings and thank you for assistance in helping me understand this code question.

I have to pull a new residential range circuit. The new range installation manual requires a standard 14-50 receptacle and power cord. However the range nameplate rating is 15kw at 240volt. 15000 / 240 =62.5 * 1.25 = 78amps which bumps up to an 80amp circuit. Should I pull an 80 amp circuit or a 50 amp circuit?

Thank you for the great advice.
I really appreciate it.
Click to expand...
2023 NEC
You can use Section 220.55 and T.220.55.
T.220.55 and Note No.1 for over 12kW. See the Note number 1, because your range is over 12 kW.

Example: Your range.... 15kW - 12kW = 3 kW x 5% for every additional kilowatt over 12kW per note No.1 of T.220.55
15kW - 12 kW = 3 kW X 5 percent.....3 X .05 = 0.15....or 1.15%

Now, you must increase T.220.55 C column (per the note no. 1) for one 8 kW range from column C and increase it by 1.15 %.

Thus, 8,000 W X 1.15 % = 9200 watts. 9200 watts / 240 volts =38.33 amps,40 amp OCPD.

The range is not a continuous load.
The maximum demand load is 8kW that you could have used had your range been less than 12kW.

Thanks for reading.
Comments accepted.
TX+MASTER#4544
 
Jaybone812 said:
Unless the manufacturer requires a 40 amp circuit, but you are not restricted to using 220.55 we have the availability to size the circuit to the kw on the nameplate if we choose to I’ve never seen a cut sheet restricts above the min allowed


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Click to expand...
2023 NEC
What if your rating is greater than 8 kW?
Say, example, it's maybe a 14.5 kW or greater rating?
What if you have several different ratings?
Have you ever had mfg's instructions for the above?
True, a single range or oven will have a rating on the name plate.
So if you size a 16.5 kW per name plate what would it be? 71 amps.
Size wire? 4 AWG or 3 AWG? It's expensive and hard to deflect when pulled into a panel.
Section 220.55 and the T. 220.55 are very helpful and if you're bidding a job like this and understand how to apply all the demand factors,
you most likely would be low bidder AND be Code compliant.

Thanks for reading
Comments accepted
TX+MASTER#4544
 
TX+ MASTER#4544 said:
2023 NEC
What if your rating is greater than 8 kW?
Say, example, it's maybe a 14.5 kW or greater rating?
What if you have several different ratings?
Have you ever had mfg's instructions for the above?
True, a single range or oven will have a rating on the name plate.
So if you size a 16.5 kW per name plate what would it be? 71 amps.
Size wire? 4 AWG or 3 AWG? It's expensive and hard to deflect when pulled into a panel.
Section 220.55 and the T. 220.55 are very helpful and if you're bidding a job like this and understand how to apply all the demand factors,
you most likely would be low bidder AND be Code compliant.

Thanks for reading
Comments accepted
TX+MASTER#4544
Click to expand...

I divert to 220.55 every time I size a dwelling unit range circuit . In my opinion there’s no reason to size the branch circuit to the kw listed on the nameplate , because when would a person really use a range in a way to reach the list kw listed on the nameplate only use it as the starting point to apply the allowed demand factors of table 220.55. You don’t need more than a 40 amp circuit for any single dwelling unit range up to 16.5kw when using 220.55 informational note 1 to size the circuit .
And obviously apply notes 2&3 for multiple ranges with different nameplate ratings if the nameplates are available at the time I do a load calculation
And no ive never had a range that the manufacturer has restricted the size the of the branch circuit to the minimum allowed when the demands of 220.55 are applied .
What I have seen multiple times is a manufacturer’s cut sheet call for a 40 or 50 amp ocpd


Sent from my iPhone using Tapatalk
 
Ravenvalor said:
Greetings and thank you for assistance in helping me understand this code question.

I have to pull a new residential range circuit. The new range installation manual requires a standard 14-50 receptacle and power cord. However the range nameplate rating is 15kw at 240volt. 15000 / 240 =62.5 * 1.25 = 78amps which bumps up to an 80amp circuit. Should I pull an 80 amp circuit or a 50 amp circuit?

Thank you for the great advice.
I really appreciate it.
Click to expand...
2023 NEC
80 AMP WOW, NO.
Free advice here at Mike Holt's Code Forum.
This is for household cooking only, not commercial.
This for only one range.
Ranges, ovens are not a continuous load.
Use type NM (romex)
See the notes below T.220.55

15kW-12kW = 3 kW
3 kW X 5% = 15kW
Increase Column C by 5% for one range
Column C one 8 kW range
1.15 X 8 Kw
1.15 X 8,000 watts = 9,200 watts
9,200 watts / 240 volts = 38.3amps
T. 310.16 Column 60 degrees C terminal
8 AWG copper at 40 amps
T.240.6 (A) 40 Amps CB

Thanks for reading
Comments accepted
TX+MASTER#4544
 
Jaybone812 said:
I divert to 220.55 every time I size a dwelling unit range circuit . In my opinion there’s no reason to size the branch circuit to the kw listed on the nameplate , because when would a person really use a range in a way to reach the list kw listed on the nameplate only use it as the starting point to apply the allowed demand factors of table 220.55. You don’t need more than a 40 amp circuit for any single dwelling unit range up to 16.5kw when using 220.55 informational note 1 to size the circuit .
And obviously apply notes 2&3 for multiple ranges with different nameplate ratings if the nameplates are available at the time I do a load calculation
And no ive never had a range that the manufacturer has restricted the size the of the branch circuit to the minimum allowed when the demands of 220.55 are applied .
What I have seen multiple times is a manufacturer’s cut sheet call for a 40 or 50 amp ocpd


Sent from my iPhone using Tapatalk
Click to expand...

Jaybone812 said:
I divert to 220.55 every time I size a dwelling unit range circuit . In my opinion there’s no reason to size the branch circuit to the kw listed on the nameplate , because when would a person really use a range in a way to reach the list kw listed on the nameplate only use it as the starting point to apply the allowed demand factors of table 220.55. You don’t need more than a 40 amp circuit for any single dwelling unit range up to 16.5kw when using 220.55 informational note 1 to size the circuit .
And obviously apply notes 2&3 for multiple ranges with different nameplate ratings if the nameplates are available at the time I do a load calculation
And no ive never had a range that the manufacturer has restricted the size the of the branch circuit to the minimum allowed when the demands of 220.55 are applied .
What I have seen multiple times is a manufacturer’s cut sheet call for a 40 or 50 amp ocpd


Sent from my iPhone using Tapatalk
Click to expand...
2023 NEC
Jaybone812: Your post

As an instructor, I must use the NEC and not speculate what may or may not happen because my students are paying me to show them how to pass the Texas TDLR electrician's license exam and they want/demand solid Code answers to show them how to perform certain calculations to arrive at the correct answer.

Question: Is it permissible per Code to install one 30 amp or one 40 amp or one 50 amp single circuit for up to three electric ovens in a dwelling and treat them as equivalent to one range?
View T. 220.55 and note 6.

Or, four ranges at 15 kW each? 4 x 15kW = 60kW in a dwelling unit load on the service?
Manufacture doesn't know what we do in the field, with a name plate or without a name plate.
Mfg. not involved in calculations.

Thanks for reading
Comments accepted.
TX+MASTER #4544
 
TX+MASTER#4544:
I appreciate and respect the fact as an educator you refuse to speculate or spread misinformation .
And note 6 applies to one counter mounted cooking unit and not more than 2 wall ovens

I read that as a cook top and not more than two ovens
So note 6 doesn’t apply
The dwelling unit service load of four 15 Kw ranges
The column c demand for 4 ranges is
17 Kw
15kw- 12kw=3 kW
3kw=15% increase
17kw x 115%=19.55Kw
A dwelling unit Service load of four 15Kw ranges.=. 19.55Kw
 
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